Gastro-laryngeal mask

ABSTRACT

A method of making a device by integrally molding. The device includes an inflatable mask comprising a relatively stiff component and a relatively soft compliant flexible component. The mask is insertable, at least when deflated, through a mouth of the patient to an inserted location within a patient. The inserted location is near a laryngeal inlet of the patient. The device also includes an airway tube and an evacuation tube coupled to the mask. The relatively soft compliant flexible component of the mask is integrally formed in a single moulding operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority under 35 U.S.C.§120 to U.S. patent application Ser. No. 11/958,946, filed Dec. 18,2007, entitled Gastro-Laryngeal Mask, the entire contents of which areincorporated herein by reference, which is a continuation of U.S. patentapplication Ser. No. 09/803,452, now U.S. Pat. No. RE39938, filed onMar. 8, 2001, entitled Gastro-Laryngeal Mask, the entire contents ofwhich are incorporated herein by reference, which is a reissue of patentapplication Ser. No. 08/921,169, now U.S. Pat. No. 5,878,745, filed onAug. 29, 1997, entitled Gastro-Laryngeal Mask, the entire contents ofwhich are incorporated herein by reference, which is a continuation ofand claims priority under 35 U.S.C. §120 to U.S. patent application Ser.No. 08/609,521, filed on Mar. 1, 1996, entitled Gastro-Laryngeal Mask,now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a laryngeal-mask airway (LMA) device, which isan artificial airway device designed to facilitate lung ventilation inan unconscious patient by forming a low-pressure seal around thelaryngeal inlet. An inflatable-ring seal surrounds an appropriatelyshaped mask which fits into the lower pharynx and is attached to a tubewhich emerges from the mouth, as for connection to medical gas-supplytubing.

More particularly, the invention relates to a variety of laryngealmasks, known as gastro-laryngeal masks (GLM), wherein provision is madefor airway assurance to the patient who is at risk from vomiting orregurgitation of stomach contents while unconscious. U.S. Pat. No.5,241,956 deals with this problem by providing an evacuation tube whichis open through the center of the inflatable seal of the laryngeal mask,thus utilizing the distal end of the inflatable ring as aninflatable-cuff formation which establishes peripherally sealedengagement to the upper sphinctral region of the oesophagus andcentrally supports the distal end of the evacuation tube. In addition,said U.S. Pat. No. 5,241,956 discloses a further inflatable cuff carriedby the laryngeal mask and by the evacuation tube, for referencinginflation against the back wall of the pharynx, thus making it possibleto establish the laryngeal-inlet seal with reduced inflation pressure,as compared with prior structures not having such an additionalinflatable cuff.

U.S. Pat. No. 5,305,743 discloses moulding techniques for manufacture ofa variety of laryngeal masks, including a gastro-laryngeal mask, whereinan inflatable back cushion provides such referencing inflation againstthe back wall of the pharynx as to widely distribute the back-wallreference, over substantially the full area of the laryngeal mask. Sucha back-cushion construction has been found to be mechanically simple andhighly effective, and U.S. Pat. No. 5,355,879 discloses such a backcushion for each of several representative laryngeal-mask constructions.

In practice, although a gastro-laryngeal-mask as described in said U.S.Pat. No. 5,355,879 works well, it has the disadvantage that the gastricevacuation channel needs to be sufficiently stiff to prevent itscollapse under the influence of the increased pressure within theback-cushion cuff, when it is inflated in the pharynx. A suitably stifftube is readily provided, but the whole device is then more difficult toinsert into the patient's throat, since insertion involves flexing thedevice around the angle at the back of the tongue. Provision of apre-curved airway tube facilitates passage around the back of thetongue, but the advancing distal tip end of the device is then morelikely to collide with the glottis (or entrance to the larynx), andindeed it may block the larynx by so doing, with consequent danger tothe patient.

BRIEF STATEMENT OF THE INVENTION

It is an object of the invention to provide an improved gastro-laryngealmask. A specific object is to meet the above object with a constructionthat specifically avoids problems or difficulties with constructions ofsaid U.S. patents.

Another specific object is to provide for ready compression and flexureof a gastric passage within a back-cushioned or cuffed gastro-laryngealmask, when the mask is in deflated condition for insertion into thepatient's throat.

Furthermore, for the deflated condition of the mask, i.e., in readinessfor insertion into the patient's throat, it is an object to enableformation of a flattened flexible leading distal-end edge to self-adaptto and resiliently ride the outer limit of curvature of the patient'sairway, throughout the insertional course of the deflated mask and intoits locating engagement with the hypopharynx.

It is a further specific object, in conjunction with the foregoingspecific objects, to provide for assurance of full patency of thegastric passage within the mask, when the mask has been inflated.

These objects are realized in the present invention by utilizing twostructural mechanisms, both of which are operative when the device isinflated; one of these mechanisms prevents lateral compression of thewall of the gastric tube, while the other of these mechanisms preventsantero-posterior compression of the wall of the gastric tube; the resultis to assure a substantially circular section within relatively softportions of the evacuation passage, as long as the device is inflatedand in installed position.

In a preferred embodiment of the invention, an artificial airway deviceto facilitate a patient's lung ventilation comprises an airway tube, anevacuation tube, and a laryngeal mask at one end of both tubes. The maskis of generally elliptical configuration and comprises a body orbackplate of relatively stiffly compliant nature, and an inflatableannular cuff or ring of relatively softly compliant nature is connectedto and surrounds the body or backplate. When inflated, the annular cuffadapts to and seals around the laryngeal inlet, and an inflatablecushion on the exterior of the inflated annulus bears against the backwall of the pharynx, to thereby forwardly load the inflated annulus intosealed relation with the laryngeal inlet, with the backplate dividingthe mask between a laryngeal-chamber side and a pharyngeal-chamber side.The relatively stiff backplate is formed for connection to the airwaytube for exclusive communication to the larynx through an opening in thebackplate; and the backplate is also configured to guide and support arelatively soft flexible evacuation tube within the pharyngeal-chamberside, from a distally open end for reception of gastric products, to aproximal end for connection to an externally discharging evacuationtube.

It is a feature of the invention that along an aligning path for theflexible evacuation tube within the pharyngeal-chamber side of the mask,a first significant angular fraction of the periphery of the flexibletube is bonded to a stabilizing portion of the backplate, and that asecond angular fraction of the periphery of the flexible tube iscontinuously bonded to the inner surface of the flexible back cushion,such that generally opposite unbonded further angular regions existbetween the bonded regions. These unbonded further regions are providedwith external stiffening ribs at a succession of axial intervals, toreinforce the unbonded regions against lateral compression when the backcushion and the inflatable ring are under inflation pressure. In thisway, inflation of the annular laryngeal-inlet sealing ring and of theflexible back cushion will assure a maximally open evacuation passagewithin the mask in inflated condition, essentially withoutantero-posterior or lateral compression of the passage. And it isfurther assured that upon deflation of the mask, evacuation-passagecompression will be essentially in the sense of achieving a squeezingand somewhat flattening deformation of the discharge passage against theformed back-plate area of evacuation-passage support; such flattening ismaximal at the oesophageal end of the discharge passage, so that, whencorrectly deflated, the device forms a wedge shape for correctinsertion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be illustratively described in detail for a presentlypreferred embodiment, and for certain other embodiments, all inconjunction with the accompanying drawings, in which:

FIG. 1 is a simplified view, generally in side elevation, for thepresently preferred embodiment of an artificial airway device, having atits distal end a laryngeal mask with a gastric-drainage feature of theinvention, the same being shown in position for use in a patient;

FIG. 2 is a fragmentary plan view, to an enlarged scale showing the backor pharynx-facing side of the mask of FIG. 1;

FIG. 3 is a plan view to the scale of FIG. 2, showing a softly compliantmoulded inflatable component of the mask, as seen from the aspect ofFIG. 2;

FIG. 4 is a plan view to the scale of FIG. 2, showing a relativelystiffly compliant rigidising or reinforcing back-plate component of themask, as seen from the aspect of FIG. 2;

FIG. 5 is a longitudinal section of the softly compliant component ofFIG. 3, to the scale of FIGS. 2 to 4 and taken generally in the verticalplane 5-5 of substantial symmetry, but prior to an inside-outdeformation step, to create the appearance of FIG. 3;

FIG. 5A is a section, taken at 5A-5A in FIG. 5;

FIG. 6 is another view in longitudinal section, to the scale of FIGS. 2to 5 and in the vertical plane 5-5 of FIG. 3, showing the relativelystiff component of FIG. 4 in assembled relation to the softly compliantcomponent of FIG. 3;

FIG. 7 is an end view, being a proximally directed view, of the distalend of the rigidising component of FIG. 4;

FIG. 8 is a simplified cross-sectional view of the inflated mask of FIG.2, taken at 8-8 in FIG. 2;

FIG. 9 is a simplified cross-sectional view of the deflated mask of FIG.2, taken at 8-8 in FIG. 2;

FIG. 10 is a view similar to FIG. 2, to show a first modification;

FIG. 11 is a view similar to FIG. 4, to show the back-plate component inthe modification of FIG. 10;

FIG. 12 is a sectional view, taken at 12-12 in FIG. 11; and

FIG. 13 is a plan view to the scale of FIG. 2 to illustrate anintermediate product which is a modification of that shown in FIGS. 5and 6.

DETAILED DESCRIPTION

Referring first to the preferred embodiments of FIGS. 1 to 9, theinvention is shown in application to an airway system comprising alaryngeal-mask unit 10 and its airway tube 11, installed through themouth 12 of a patient. The mask unit 10 may be generally as described inany of the above-identified U.S. patents and therefore need not now bedescribed in detail. It suffices to say that mask unit 10 comprises arelatively stiff body or backing-plate member, generally indicated at13, and an apertured relatively thin body-membrane portion or panel 13′having an aperture or lumen 14 through which the airway tube 11 canestablish a free externally accessible ventilation passage, via thepatient's mouth 12 and throat 15, and past the epiglottis 16 to thelarynx 17. The body member 13 of mask 10 may be described as generallydome-shaped, with its concave side terminating in a generally ellipticalfooting, and facing the laryngeal inlet; and its convex side faces thebackwall of the pharynx. Body 13 is suitably of an elastomer such assilicone rubber and relatively stiff; and body member 13 is surroundedby an inflatable ring 18 which is generally elliptical and which iscircumferentially united to body member 13 in essentially a singleplane. The inflatable ring 18 may also be of silicone rubber, althoughpreferably relatively soft and flexible compared to body member 13. Anexternally accessible tube 19 is the means of supplying air to theinflatable ring 18 and of extracting air from (and therefore collapsing)ring 18 for purposes of insertion in or removal from the patient;check-valve means 21 in tube 19 will be understood to hold a giveninflation or to hold a given deflation of ring 18.

In the installed position of FIG. 1, the projecting but blunted distalend 27 of ring 18 is shaped to conform with the base of the hypopharynxwhere it has established limited entry into the upper sphinctral regionof the oesophagus 24. The back side of body member 13 is covered by athin flexible panel 25 (FIG. 2) which is peripherally bonded to theinflatable ring 18 (FIG. 1) and in sealed engagement at peripheral line25′ around the entrance of tubes 11 and 23 to the mask structure todefine an inflatable back cushion which assures referencing to the backwall of the pharynx and thus is able to load the mask unit forward forenhanced effectiveness of inflated-ring sealing engagement to thelaryngeal inlet. The inflated ring, thus-engaged to the laryngeal inlet,orients the distal-end of the airway tube 11 at an acute angle to thegeneral plane of ring 18 and in substantial alignment with the axis ofthe laryngeal inlet, for direct airway communication only with thelarynx 17.

The laryngeal-mask unit 10 is of the GLM variety in which an evacuationtube 23 (FIG. 2) serves for extraction and external removal ofgastric-discharge products from the oesophagus. Tube 23 follows thegeneral course of the airway tube 11, with sealed entry alongside airwaytube 11, beneath the back-cushion panel 25, and with passage through theinterior of ring 18, near the distal end of the mask; in FIG. 3, thedistally open end of the evacuation tube 23 is defined by a re-entranttubular conduit formation 26 integrally formed with the relatively softmaterial of ring 18. As explained in U.S. Pat. No. 5,241,956,inflation-air supply to the back cushion may be the same (19) as forring 18, or separate inflating means (not shown) may be provided forthese separate inflatable means.

More specifically, for the particular construction shown, the relativelysoftly compliant flexible components may be integrally formed in asingle moulding operation, in which the moulded intermediate product isan inside-out version of what will become the finished more flexiblepart of the finished mask unit 10. The moulded intermediate product maythus have the appearance shown in FIG. 5, following the techniquedescribed in U.S. Pat. No. 5,305,743, to which reference is made fordetailed description. It suffices here to identify the inflation-airinlet formation 28, directed inwardly on a central axis 29 which alsoincludes the outwardly directed distal-end formation of the evacuationtube 26; the central axis 29 may also be understood as identifying theequator plane (perpendicular to the drawing of FIG. 5) which applies tothe inflatable annular ring 18, after evacuation tube 26 has been swungupward (counterclockwise), in the sense suggested by arrow 30, andgenerally for 180.degree. of rotation about an axis 31, which (axis 31)is normal to the plane of the drawing of FIG. 5. This 180.degree.rotation tucks tube 26 into the flange relatively large edge 32 of theopen skirt of the moulded intermediate product of FIG. 5 and makes it asimple matter to turn the remainder of the skirt inside-out, thusdefining ring 18, with the edge flange 32 seated on a ledge 33 of theupper dome-shaped feature (body-membrane portion or liner 13′) of themoulded intermediate product.

In the preferred form shown, the mask body member 13 (FIGS. 4 and 7) isa separately moulded component of relatively stiff nature as compared tothe moulded intermediate product of FIG. 5. Stiffness vs. softness willbe understood to be relative terms and not necessarily to imply thatthese components are formed from different materials.

In FIG. 4, the body component 13 is seen to comprise an apertured panelwhich is essentially a moulded dome or bowl 34 having a concave innersurface which conforms to the convex moulded contour of the dome shape35 of the relatively soft (i.e., thin-walled) component of FIG. 5, thesecomponents being shown in FIG. 6 in assembled relation. Relativestiffness (thickness) in the bowl or dome 34 of FIG. 4 is generally inthe range 2 to 5 mm, with gradually reducing thickness for greaterflexibility in approach to the lower or distal end. The bowl or dome 34has a peripheral edge which terminates in a single plane, for adhesivelybonded seating to the ledge 33 of the relatively soft component of FIG.5, after making the inside-out inversion.

The stiffness of body member 13 is greatest in the region ofproximal-end seating to ledge 33, above which an inlet-air formation 36is oriented on an axis 37 which is not only inclined at an acute angle.alpha. to the plane of seating to ledge 33, but is also laterallyoffset from the central longitudinal plane of symmetry of the mask,denoted 5-5 in FIG. 3. Relative stiffness of body member 13 is alsoenhanced (i) by the fact that its distal half features a slot 38 ofwidth less than the diameter of the re-entrant distal-end tube 26, (ii)by the fact that the re-entrant tube 26 is adhesively retained incradled support by and between confronting edges of slot 38, and (iii)by the fact that the distal end of evacuation tube 23 is preferablypreformed (as seen in FIG. 2) with a quarter-turn helical advance totrack the course of slot 38 in the upper or proximal half of body member13. The evacuation tube 23 is preferably relatively stiff, e.g.,stiffness (thickness) in the order of magnitude of the material at theupper (proximal) half of body member 13, and is seen in FIG. 2 to havetelescoping fit to the proximally directed upper end of re-entrant tube26; this is an adhesively sealed fit.

Stated in other words and in explanation of the distal and proximalhalves of the body member 13 and the relation of these halves to therelatively thin material and distal-half extent of re-entrant tubularconduit 26, said tubular conduit may be said to extend proximally toapproximately 50 percent of the longitudinal extent of the inflatablering 18; alternatively, said tubular conduit 26 may be said to extendproximally to at least substantially 50 percent of the longitudinalextent of the inflatable ring 18, consistent with the drawings of FIGS.2, 3, and 6. Furthermore, as seen in FIG. 4, the distal half ofbacking-plate member 13 is essentially straight, thus determining astraight proximal direction of tubular conduit 26 for substantially thedistal half of the longitudinal extent of the mask.

As also seen in FIG. 2, the back-cushion panel 25 covers a substantialpart of the posterior surface of the mask, being peripherally sealedaround the generally elliptical course of inflatable ring 18, and alsobeing centrally adhered to the re-entrant tube 26 for substantially theentire length of tube 26, as suggested by cross-hatching 39. Finally, toassure integrity of the inflatable ring 18, the re-entrant tube 26 isadhesively sealed to the adjacent edges of tube-26 local passage throughring 18 at the distal location designated 40 in FIG. 3; for purposes ofavoiding undue complexity in the drawings, this adhesively sealed regionis not shown but will be understood to be along the line of tube-26intercept with locally adjacent walls of inflatable ring 18. In FIG. 5,this intercept line is accounted for by a local cut-out 40′ at thedistal end of the skirt of the intermediate product of FIG. 5.

The simplified sectional diagram of FIG. 8 illustrates the functionalcooperation of described component parts and features of the describedgastro-laryngeal mask construction, in inflated condition, to accountfor diametrically opposite section cuts through right and left halves ofthe inflatable ring 18, spaced by sealed fit of body member 13 to theinner profile of ring 18. The back-cushion panel 25, being centrallyadhered at 39 to the upper central region of re-entrant tube 26,provides a lifting force which is in the direction to hold open theevacuation tube and, therefore, not to collapse tube 26 when the backcushion is inflated; without this force, in opposition to a retainingforce attributable to adhesive connection to body member 13 (along edgesof slot 38), there would be no tendency to hold a softly compliant tube26 against collapse, in that the cushion panel would outwardly expanditself to a bowed shape 25′ suggested by phantom outline in FIGS. 6 and8.

Preferably, the effective arcuate extent of adhesive connection 39 is inthe range 45.degree. to 90.degree. about the central axis of tube 26, asseen in FIG. 8. Preferably also, the adhesive connection of tube 26along the straight edges of the distal half of slot 38 accounts for acorresponding range of support of tube 26 against collapse in thecircumstance of back-cushion inflation. In other words, inflation of thering 18 and back cushion 25 will assure developed vertical forces tohold the evacuation passage of re-entrant tube 26 in substantially opencondition, but the transversely opposed arcuate regions (each ofapproximately 90.degree. arcuate extent) between these adhesivelyconnected regions are vulnerable to compressionally inward bowing, thusreducing the sectional area of tube 26 while the mask is inflated. Theinvention resolves this vulnerability by providing axially spacedstiffening ribs or ridges 42 as integral formations of the re-entranttube 26, in the initially moulded intermediate product of FIG. 5. Asshown, there are three mutually opposed pairs of ridges 42, at axialspacings which are in the order of the unstressed bore diameter of tube26. For the indicated silicone-rubber material of the product of FIG. 5,the incremental local thickness at ridges 42 is suitably twice or threetimes the otherwise uniformly thin moulded product of FIG. 5, as seen inFIG. 5A.

In FIG. 8, a section taken near the location of tube 26 connection tothe more stiffly compliant evacuation tube 23, the inflated condition ofthe GLM mask of the invention is seen to have an overall “height”dimensions H.sub.1, meaning front-to-back (i.e., laryngealinlet-to-pharynx back wall). When the mask is deflated, this dimensionH.sub.1 is seen to be reduced by approximately 50 percent, as shown atH.sub.2 in FIG. 9 for the deflated condition of the same mask. Whendeflated, as has been pointed out in U.S. Pat. No. 5,297,547, the ring18 collapses into flattened double walls (marked 18′) which are upwardlydished; and although deflation does little to compress tube 26 otherthan at the region 39′ of adhesion to the back-cushion panel 25, theoverall deflated extent H.sub.2 is essentially unchanged from thedimension H.sub.2 which applies for collapse of ring 18. On the otherhand, at the distal end of the mask, the collapse of ring 18 isoperative upon the formed distal-end opening 43 of tube 26 to somewhatflatten the opening 43, into a generally shovel-shaped distal lipfeature which merges smoothly into the adjacent upwardly disheddouble-wall. shape 18′ shown in the longitudinal mid-section of FIG. 9.

It will be appreciated that the GLM device described thus far has anairway tube 11 that is of larger diameter than the evacuation tube 23;in this circumstance, the airway tube 11 is large enough to accommodateguided insertion of an endotracheal tube. The tubes 11, 23 enter thedescribed laryngeal mask 10 in side-by-side relation and are preferablyadhesively secured to each other in this side-by-side relation, andalong their full longitudinal extent, in order to provide a measure oftorsional resistance against twisting, thereby aiding a medicallyqualified person in quickly and correctly installing a fully deflatedGLM in a patient, with assurance that, upon inflation of ring 18 and theback-cushion panel 25, an exclusive and sealed airway connection will beestablished to the laryngeal inlet, via lumen 14 and from the airwaytube 11; concurrently, a similarly exclusive evacuation connection isestablished to the upper sphinctral region of the oesophagus, via thedistal-end opening 43 of tube 26, through the evacuation tube 23, and tosuitable waste-collection means (not shown) external to the patient.

More specifically as to insertion of the fully deflated GLM device in apatient, it will be understood that a range of GLM sizes is availablefrom which to select a sufficiently correct size for the patient.Deflation is accomplished via external means (not shown) and viacheck-valve means 21 to hold the deflated condition wherein the domeshape of body member 13 rises from within the dished peripheral lip 18′of the collapsed ring 18. A skilled operator is quickly able to developthe desired appearance of the GLM in its deflated state; but for auniformly correct deflated shaping, it is recommended to use a formingtool as described in U.S. Pat. No. 5,711,293.

When correctly shaped and in its deflated condition, and at the distalend of the GLM, the opening 43 will have been flattened, and this distalend merges with the peripheral lip 18′ of the collapsed ring 18. Notingthat the entire distal half of the mask is of relatively soft material,stiffened only by indicated adhesive connection, the distal end projectsdistally and at its upwardly flared merge with lip 18′, for lowacute-angle incidence to the posterior arcuate profile of the patient'sthroat passage. That being the case, a medical technician need only makesure that upon inserting the mask via the patient's mouth and throat,the flattened distal end rides the outer (posterior) arcuate contour ofthe patient's airway, in that the softly flexible nature of the distallyprojecting and somewhat flattened distal end will be flexiblyself-adapting to local irregularities (if any) in the course of passageinto the pharynx; final insertional location is noted by an increase inencountered resistance, upon distal-end engagement of the GLM with theupper sphinctral region of the oesophagus. At this juncture, inflationair supplied via line 19 and retained by check-valve means 21establishes (i) the described seal of ring 18 to the laryngeal inlet,(ii) back cushion (panel 25) contact with the back wall of the pharynx,and (iii) full opening of the evacuation tube 26 for maximumaccommodation of a possible gastric discharge from the oesophagus.

Beyond what has been described, FIG. 10 illustrates at phantom outline26′ that the flexible length of the re-entrant tube 26 may be of evengreater length than the approximately half-mask length shown by thesolid lines of FIG. 5. In that event, arcuate stiffener ridges asdescribed at 42 will be preferred, as long as lateral support is neededto prevent side-wall collapse of the extended tube 26′, in the inflatedcondition of the mask, i.e., including inflation of back-cushion panel25.

FIGS. 10 to 12 illustrate another GLM embodiment wherein an airway tube50 and an evacuation tube 51 are of equal size, adhered (as suggested at52) to each other in side-by-side relation for torsionally resistant andsymmetrically positioned entry into corresponding side-by-side ports 53,54 of the dome like moulded backing plate or body member 55 of FIGS. 11and 12. The backing plate 55 may be similar to plate 13 of FIG. 4,except that in FIG. 11 the somewhat helically arcuate conduit path fromthe inserted distal end of evacuation tube 51 to the point 56 of softlycompliant re-entrant tube (26) connection is provided by an integralpassage formation 57 of the backing plate 55. At point 56 in FIG. 11,the formation 57 is seen to be in the central vertical plane 58 ofsymmetry of the bowl or dome-shape of backing plate 55 and in alignmentfor accepted proximal-end insertional accommodation of a re-entrant tube26 of thin-walled material to which backing plate 55 is to be assembled,with edges of the straight slot 38′ supporting tube 26 in the manneralready described. Also integrally formed with backing plate 55 is aninlet-connection counterbore for coupled connection of airway tube 50 tothe laryngeally exposed side of the mask. Features in FIG. 10, such asthe back-cushion panel 25, the inflatable ring 18, and the adhesivelybonded connection 39 of panel 25 to tube 26 are all as previouslydescribed.

It will be understood that the inside-out technique described inconnection with FIGS. 5 and 6 for initially moulding and then invertingthe skirt of the moulded product, is but one illustration of a way tocreate the mask and its inflatable ring, in which case the flexibledrainage conduit does not get inverted. That being the case, thereinforcement ribs 42 are initially formed portions of the outer surfaceof the moulded product. On the other hand, another technique for formingthe mask with its inflatable ring, involves moulding the mask bowlintegrally with an elliptically configured product as shown in FIG. 13,wherein completion of inflatable-ring (18) integrity requires only anadhesively bonded completion of the ring peripherally around the innersubstantially elliptical profile, where backing-plate (13) connection isalso adhesively secured. In that case, the drainage tube 26 isintegrally-moulded with the non-invertible ring (18), so that aninversion of tube 26 is necessary, to have it project re-entrantly, inthe proximal direction, and the moulded product which is to becomeinflatable ring 18 must be cut away as at 40, to permit inverted tube 26to “pass through” the inflatable ring, in order to develop arelationship which is suggested by FIG. 5. Of course, if tube 26 is tobe inverted, the reinforcement ribs 42 are preferably integrally formedas radially inward rib reinforcements or discontinuities in the mouldedbore of tube 26. Inversion of tube 26 places these rib reinforcements onthe outer surface of tube 26, so that the bore of tube 26 is inherentlysmooth.

1. A method of making a device including: (A) an inflatable maskcomprising a relatively stiff component and a relatively soft compliantflexible component, the mask being insertable, at least when deflated,through a mouth of a patient to an inserted location within the patient,the inserted location being near a laryngeal inlet of the patient; (B)an airway tube coupled to the mask, the airway tube extending from aproximal end located outside of the patient's mouth through aninterdental gap to the mask when the mask is at the inserted location,the interdental gap being a space between the patient's lower teeth andthe patient's upper teeth; and (C) an evacuation tube for communicationwith an esophageal inlet of the patient, the evacuation tube beingcoupled to the mask, the evacuation tube extending from a proximal endlocated outside of the patient's mouth through the interdental gap tothe mask when the mask is at the inserted location; wherein said methodcomprises integrally forming the relatively soft compliant flexiblecomponent of the mask in a single moulding operation.
 2. A method ofmaking a device according to claim 1, wherein integrally forming therelatively soft compliant flexible component of the mask comprisesintegrally forming an inflation-air inlet formation, an outwardlydirected distal-end tube and an open skirt.
 3. A method of making adevice according to claim 2, further including a step of rotating theoutwardly directed distal-end with respect to the open skirt and tuckingthe integrally formed distal-end tube into a flange of the open skirt.4. A method of making a device according to claim 3, further including astep of turning a portion of the skirt inside-out, thus defining a ring.5. A method of making a device according to claim 4, further comprisingthe step of adhesively bonding the relatively stiff component to therelatively soft component after the skirt has been turned inside-out. 6.A method of making a device according to claim 5, wherein the relativelystiff component comprises a back-cushion panel, and the back-cushionpanel is centrally adhered to the inwardly directed distal-end tube ofthe relatively soft component.
 7. A method of making a device accordingto claim 5, wherein the edges of the inwardly directed distal-end tubeare adhesively sealed to the locally adjacent walls of the ring.
 8. Amethod of making a device according to claim 5, further comprisingadhesively sealing the evacuation tube to the inwardly directeddistal-end tube after the relatively stiff component has been adhesivelybonded to the relatively soft component.
 9. A method of making a deviceaccording to claim 2, wherein integrally forming the mask comprisesintegrally forming axially spaced stiffening ribs or ridges located onthe outwardly directed distal-end tube.
 10. A method of making a deviceaccording to claim 9, wherein the axially spaced stiffening ribs orridges are integrally formed on the inner surface of the outwardlydirected distal-end tube so that after the outwardly directed distal-endtube is tucked into the flange of the open skirt the axially spacedstiffening ribs or ridges are located on the outer surface of theinwardly directed distal-end tube.